I would agree with most of what has been said, a good breeder should look at the bigger picture, not just breed for looks but also disease resistance, vigour, not bottleneck genes entirely and put a healthy genetics representation onto the market place that offers some stability of the intended genes he or she wanted to develop.
I wouldn't include Matt Riot of riot seeds in that personally, as i don't consider what he does seed breeding, but that might just be me, and i always questions those who appoint themselves as genetic authorities rather than earn that spot.
There are so many amazing breeders out there currently, look for those who seem to pass off the image and message that you would like to portray, look for realistic pricing, and well develop seed lines with a high occurrence of high quality offspring. If you are looking for a certain gene do you homework and see who has the closest to the source, if looking for Triangle Kush or the white then swamp boys, if looking for a wide array of elite clone hybrids then Archive or CSI humboldt
These include for me, amongst many others
Bodhi seeds
Archive
Bloom Seed co
CSI humboldt
Relentless genetics
Symbiotic
Thugpug
Swamp boys
Eskobar seeds
Karma genetics
and many many more, but be careful, its a seed business and some people just want you hard earned cash